Front end apron assembly for a motor vehicle

ABSTRACT

The modular front end forms the front portion of a motor vehicle. The modular front end includes a bulkhead defining a plurality of integrally formed attachment mounts. A drive train assembly carrying at least an engine of the motor vehicle is attached to the bulkhead at the attachment mounts. A crash energy absorption assembly is attached to the attachment mounts on the bulkhead and generally extends around the drive train assembly. An apron assembly is attached to the bulkhead at the attachment mounts and is generally positioned above the drive train assembly and crash energy absorption assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a division of U.S. patent application Ser.No. 10/271,462, filed Oct. 16, 2002, and entitled “Modular Front End ForA Motor Vehicle,” which claims the benefit of U.S. Provisional PatentApplication Serial No. 60/329,802, filed Oct. 16, 2001, and entitled“Modular Front End For Passenger Cars And Light Trucks, Joining AnIntegrated Drive Train Module, Apron-Cum Energy Module And Crash EnergyManagement Module To An Integrated Structural Cowl”, the full disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to motor vehicles, suchas passenger cars and light trucks. More particularly, the presentinvention relates generally to a multi-component front end for a motorvehicle, which advances the methods by which motor vehicles areassembled.

[0004] 2. Description of Related Art

[0005] Currently, the front ends of most motor vehicles are built intothe vehicle body one piece or component at a time. The installation ofliterally hundreds of different components in the motor vehicle frontend requires the manufacturer to maintain lengthy, complex, and costlyassembly lines as well as extensive tooling and fixtures. Thiscomplexity is due not only to the high number of parts involved, butalso the assembly methods currently used in the automotive industry andthe amount of on-line adjusting and repair that is often needed tocorrect assembly defects. Additionally, the well-known assembly lineprocess is highly labor intensive, again due mainly to the high numberof parts and assembly methods currently used in the automotive industry.

[0006] Typically, once a painted vehicle body comes to the finishassembly line, hundreds of individual components are assembled to thevehicle body. The numerous individual components are used to completethe suspension system, steering and braking system, power train, coolingsystem, electrical system, etc. As stated, the individual componentscomprising these systems are typically added to the vehicle bodyone-by-one or in small subgroups to finish the assembly of the motorvehicle.

[0007] The large number of components required to assemble a motorvehicle requires the assembly line to be extremely long and requiresmany people to accomplish numerous discreet tasks along the assemblyline. This makes the process of motor vehicle assembly unnecessarilyslow and complicated and adversely affects the quality and reliabilityof the motor vehicle when it is completed. Additionally, the confinedspace within which the workers operate makes on-line service and repairtasks difficult and even dangerous. The overall complexity of thecurrent system for assembling motor vehicles is unnecessarily slow andexpensive and there is considerable room for improvement.

SUMMARY OF THE INVENTION

[0008] The present invention applies the general concept of usingmodules or assemblies in the manufacturing of motor vehicles. Theconcepts and embodiments disclosed hereinafter may be applied to otherindustries that utilize the long-standing assembly line technique forproducing finished products, such as the aircraft, agriculturalmachinery, truck manufacturing, and mining vehicle industries.Generally, the present invention is a motor vehicle comprising a vehiclebody having a pre-assembled, modular front end. The modular front end iscomprised of several sub-modules or sub-assemblies, as discussedhereinafter.

[0009] The modular front end is based on the concept of “functionallydecoupling” the several sub-modules or sub-assemblies from each other.In front end assembly techniques currently practiced in the art, thevarious elements or components of the front end are substantiallyinterconnected or related. In contrast, the modular front end of thepresent invention has the various sub-assemblies comprising the frontend substantially functionally isolated from one another. The separatefunctions of the sub-assemblies, which will be discussed hereinafter,are substantially independent from one another allowing any onesub-module or sub-assembly to be individually replaced without affectingthe other sub-modules or sub-assemblies. This allows the sub-modules orsub-assemblies to be comprised of smaller and lighter individualcomponents or parts, which is not easily possible in the “inter-related”front end structures generally found in the prior art. The use ofseparate and distinct sub-modules or sub-assemblies in the modular frontend allows the overall size of the modular front end to be reducedbecause the sub-assemblies may be compact tightly within the modularfront end. The smaller front end made possible by the modular front endof the present invention improves the overall driving and handlingcharacteristics of the motor vehicle. For example, the smaller front endis lower in profile than those currently known in the art, whichimproves the driver's view of the road and aids the driver in performingroutine vehicle operations such as parking, turning, etc.

[0010] Generally, the modular front end comprises a bulkhead having aplurality of preferably integrally formed attachment mounts, a drivetrain assembly attached to the bulkhead at the attachment mounts, acrash energy absorption assembly attached to the bulkhead at theattachment mounts and, further, an apron assembly attached to thebulkhead assembly at the attachment mounts. The apron assembly may be atleast partially supported in the vertical direction by the crash energyabsorption assembly. The drive train assembly, crash energy absorptionassembly, and apron assembly are each preferably attached mechanicallyto the bulkhead.

[0011] The bulkhead is preferably a cast bulkhead comprising a pluralityof integrally formed attachment mounts. The bulkhead may be cast fromaluminum alloy as a unitary body. The bulkhead may also be comprised ofa plurality of individually cast components. The bulkhead may beprovided as part of a bulkhead assembly. The bulkhead assembly maycomprise a cast bulkhead defining a plurality of integrally formedattachment mounts and at least one structural member of the motorvehicle attached to the bulkhead. The bulkhead assembly may furtherinclude one or more electrical components attached to the bulkhead.

[0012] The bulkhead may define at least one hollow cavity formed thereinfor increasing strength and rigidity of the bulkhead. The at least onehollow cavity may be filled with a cast-in-place core, preferably analuminum foam core. The hollow cavity may also be filled with polymericfoam. The at least one structural member may comprise a pair of doorhinge pillars attached to attachment mounts located at opposite ends ofthe bulkhead. The at least one structural member may also comprise apair of rocker panels attached to a bottom end of the bulkhead oppositethe door hinge pillars. Additionally, the at least one structural membermay comprise a pair of windshield support pillars attached to a top endof the bulkhead. The at least one structural member may further comprisea windshield cross member attached to the top end of the bulkheadbetween the windshield support pillars.

[0013] The bulkhead may comprise a first side for facing an enginecompartment of the motor vehicle and a second side for facing apassenger compartment of the motor vehicle. A pair of hood hinges, whichmay each include a hood lift assist mechanism, may be attached toattachment mounts located on the first side of the bulkhead forsupporting a hood of the motor vehicle. The electrical component(s) ispreferably attached to the first side of the bulkhead, but may beattached to the second side facing the passenger compartment. Theelectrical component(s) may include, for example, a windshield wipermotor and/or an electrical junction box.

[0014] The drive train assembly generally comprises a drive trainsupport and a power train assembly attached to the drive train support.The drive train support comprises a pair of elongated support membersthat are configured for attachment, preferably by mechanical means, to abulkhead of the motor vehicle. By mechanical attachment or means, it ismeant that mechanical fasteners, such as nuts and bolts, rivets, and thelike are preferably used to attach the various elements described inthis disclosure, and may include rubber isolation mounts (i.e.,bushings), where necessary, to minimize vibration between elements. Thedrive train support further comprises a cross member interconnecting thesupport members. The support members are further configured to supportthe power train assembly such that the power train assembly iscantilevered from the support members and bulkhead forward of the crossmember.

[0015] The support members and cross member may be made of aluminumalloy. The support members may be cast aluminum alloy support members.The cross member may be an extruded aluminum alloy cross member. Thesupport members each comprise a top end and a bottom end. The crossmember preferably connects the top ends of the support members. Thecross member may be connected mechanically to the support members.

[0016] In the modular front end, the power train assembly is attached tothe support members such that the power train assembly is cantileveredfrom the support members and bulkhead forward of the cross member. Thesupport members may be attached mechanically to the bulkhead. Themechanical attachment may comprise at least one isolation mount fordampening vibration of the power train assembly. The power trainassembly may comprise an engine and transmission of the motor vehicle.The engine may be mechanically attached to the drive train support andcomprise at least one isolation mount for dampening vibration of theengine. The transmission may be mechanically attached to the drive trainsupport and comprise at least one isolation mount for dampeningvibration of the transmission. The drive train assembly may furthercomprise a steering gear of the motor vehicle attached to the bottomends of the support members and interconnecting the bottom ends of thesupport members. Further, the drive train assembly may comprise a brakeand suspension assembly for each front wheel of the motor vehicle. Thebrake and suspension assemblies are attached to the support members,respectively, and preferably the lower ends of the support members. Thebrake and suspension assemblies may each comprise a control armconnected to the respective support members preferably mechanically.

[0017] The crash energy absorption assembly generally comprises anelongated bumper beam, a pair brackets attached to the bumper beam, anda pair of tubes supported by the brackets. The tubes each have a firstend and a second end. The first ends of the tubes are supported by thebrackets. The second ends of the tubes may be attached to the bulkheadat the attachment mounts. A crosstie may interconnect the brackets. Thebumper beam, brackets, and tubes may be made of aluminum alloy.

[0018] The bumper beam may define a substantially open cross section,which may be at least partially, but preferably completely, filled withpolymeric foam. The bumper beam may define a substantially Σ-shapedcross section. The substantially Σ-shaped cross section may comprise arear wall connected to substantially parallel top and bottom walls. Thebrackets may be attached to the bumper beam opposite the rear wall.

[0019] The tubes may be at least partially filled with polymeric foam.The tubes may comprise a tube with a cross-sectional profile selectedfrom the group consisting of a circle, a square, an oval, a rectangle, ahexagon, and a combination thereof. The tubes may have differentcross-sectional profiles. The brackets are preferably attachedmechanically to the bumper beam. The brackets may define socketsconfigured to receive the first ends of the tubes. The tubes may besecured mechanically in the sockets. The bumper beam may define anoverall curved shape. In the modular front end, the second ends of thetubes are attached to the bulkhead at the attachment mounts. Thebrackets may be taper and flare brackets, which absorb impact energyusing the taper and flare principle known in the art. Alternatively, thebrackets may be conventional brackets and the tubes may be crush tubesfor absorbing crash energy during a collision.

[0020] The apron assembly generally comprises an apron and, preferably,at least one engine accessory of the motor vehicle attached to theapron. The apron generally comprises a substantially C-shaped, unitaryapron member having a depending front portion and a substantiallyC-shaped apron rail attached to a top end of the apron member. The apronmember defines at least one integrally formed accessory attachment mountfor mounting the at least one engine accessory of the motor vehicle. Theapron rail is attached to the top end of the apron member and isconfigured for attachment to the bulkhead. Preferably, the ends of theapron rail are attached to the bulkhead. The apron rail may beconfigured for mechanical attachment to the bulkhead. The apron rail ispreferably attached mechanically to the apron member. The apron memberis preferably formed of molded plastic material and the apron rail ispreferably made of aluminum alloy. The apron rail may be a hydro-formedtube defining differing cross-sectional areas along its length, whichprovide mounting locations for various front end components of the motorvehicle such as the vehicle fenders. The at least one accessoryattachment mount may comprise a plurality of openings defined in thefront portion of the apron member.

[0021] The at least one engine accessory may be a radiator and coolingfan assembly and the accessory attachment mount may be an openingdefined in the front portion of the apron member. The radiator andcooling fan is supported in the opening. The at least one engineaccessory may be an air conditioning condenser and the attachment mountmay be a second opening defined in the front portion of the apronmember. The air conditioning condenser is supported in the secondopening. Additionally, the at least one engine accessory may be atransmission oil cooler and the accessory attachment mount may be athird opening defined in the front portion of the apron member. Thetransmission oil cooler is supported in the third opening. Further, theat least one engine accessory may be a battery and the accessoryattachment mount may be an integrally formed battery hold-down. Thebattery is supported in the battery hold down. The apron assembly mayfurther comprise fenders attached to the apron rail and/or headlightsattached to the front portion of the apron member. Other possible engineaccessories include fluid reservoirs for the radiator and coolingassembly, windshield wiper fluid etc.

[0022] The present invention is also a method of assembling a modularfront end for a motor vehicle. The method comprises the steps ofproviding a bulkhead having a plurality of attachment mounts; attachinga drive train assembly to the bulkhead at the attachment mounts;attaching a crash energy absorption assembly to the bulkhead at theattachment mounts; and attaching an apron assembly to the bulkhead atthe attachment mounts. The bulkhead may be pre-attached to the vehiclebody and the various assemblies identified hereinabove assembled to thepre-attached bulkhead. Thus, the step of providing the bulkhead includesboth a separate, stand alone bulkhead that is to be attached to avehicle body, and a bulkhead that is pre-attached to a vehicle body.

[0023] The method may further comprise the step of casting the bulkheadas a unitary bulkhead. The attachment mounts are preferably formedintegrally with the unitary bulkhead. The bulkhead may be cast fromaluminum alloy. The method may further comprise the step of attaching atleast one structural member of the motor vehicle to the bulkhead.

[0024] The bulkhead may comprise a first side for facing an enginecompartment of the motor vehicle and a second side for facing apassenger compartment of the motor vehicle. The method may comprise thestep of attaching at least one electrical component of the motor vehicleto the first side of the bulkhead. The drive train assembly, crashenergy absorption assembly, and apron assembly may be attachedmechanically to the attachment mounts located on the first side of thebulkhead.

[0025] The drive train assembly may comprise a drive train support and apower train assembly. The power train assembly may comprise an engineand a transmission of the motor vehicle attached to the drive trainsupport. The step of attaching the drive train assembly to the bulkheadmay comprise attaching the drive train support to the bulkhead at theattachment mounts such that the power train assembly is cantileveredfrom the drive train support and bulkhead. The power train support maycomprise a pair of support members each having a top end and a bottomend and a cross member connecting the top ends of the support members.The method may further comprise the step of attaching a steering gear ofthe motor vehicle to the bottom ends of the support members tointerconnect the support members. The drive train assembly may furthercomprise a brake and suspension assembly for each front wheel of themotor vehicle. Further, the method may comprise the step of attachingthe brake and suspension assemblies to the support members,respectively.

[0026] The crash energy absorption assembly may comprise an elongatedbumper beam, a pair of brackets attached to the bumper beam, and a pairof tubes each having a first end and a second end. The first ends of thetubes may be supported by the brackets. The step of attaching the crashenergy absorption assembly to the bulkhead may comprise attaching thesecond ends of the tubes to attachment mounts preferably located on thefirst side of the bulkhead.

[0027] The apron assembly may be partially supported in the verticaldirection by the crash energy absorption module. The apron assembly maycomprise an apron member and at least one engine accessory of the motorvehicle attached to the apron member. The method may further comprisethe step of attaching the at least one engine accessory of the motorvehicle to the apron member. The at least one engine accessory may be aradiator and cooling fan assembly, an air conditioning condenser, atransmission oil cooler, and/or a battery. Other possible engineaccessories include fluid reservoirs for the radiator and coolingassembly, windshield wiper fluid etc. The apron member may besubstantially C-shaped and have a depending front portion. The apronassembly may further comprise a substantially C-shaped apron rail. Themethod may comprise the step of attaching the apron rail to a top end ofthe apron member. The ends of the apron rail may be configured forconnection to the bulkhead at the attachment mounts. The step ofattaching the apron assembly to the bulkhead may comprise attaching theends of the apron rail to the bulkhead at the attachment mounts.Furthermore, the method may comprise the steps of attaching one or morefenders of the motor vehicle to the apron rail, and attaching headlightsof the motor vehicle to the front portion of the apron member.

[0028] Further details and advantages of the present invention willbecome apparent from owing detailed description when read in conjunctionwith the drawings, wherein like designated with like reference numeralsthroughout.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a perspective view of a motor vehicle having a modularfront end in accordance with the present invention;

[0030]FIG. 2 is a perspective view of the modular front end shown inFIG. 1;

[0031]FIG. 3 is a perspective view of a bulkhead assembly used in themodular front end of FIGS. 1 and 2;

[0032]FIG. 4 is a perspective view of a bulkhead used in the bulkheadassembly of FIG. 3 showing the passenger compartment facing side of thebulkhead;

[0033]FIG. 5 is a perspective view of the bulkhead used in the bulkheadassembly of FIG. 3 showing the engine compartment facing side of thebulkhead;

[0034]FIG. 6 is a perspective view of the bulkhead assembly generallyshowing the engine compartment facing side of the bulkhead;

[0035]FIG. 7 is a perspective view of the bulkhead assembly generallyshowing the passenger compartment facing side of the bulkhead;

[0036]FIG. 8 is a perspective view of a drive train assembly used in thein the modular front end of FIGS. 1 and 2;

[0037]FIG. 9 is a side view of the drive train assembly of FIG. 8;

[0038]FIG. 10 is a perspective view of a drive train support used in thedrive train assembly of FIG. 8;

[0039]FIG. 11 is a perspective view of the drive train support of FIG.10 generally viewed from the opposite or reverse side;

[0040]FIG. 12 is a perspective view of the drive train assembly of FIG.8 with the bulkhead removed and showing the various components of thedrive train assembly;

[0041]FIG. 13 is a bottom view of the drive train assembly of FIG. 8;

[0042]FIG. 14 is a perspective view of a crash energy absorptionassembly used in the modular front end of FIGS. 1 and 2;

[0043]FIG. 15 is a second perspective view of the crash energyabsorption assembly used in the in the modular front end of FIGS. 1 and2;

[0044]FIG. 16 is a perspective view of an apron assembly used in the inthe modular front end of FIGS. 1 and 2;

[0045]FIG. 17 is a perspective view showing an apron of the apronassembly of FIG. 16;

[0046]FIG. 18 is a perspective view of the apron assembly of FIG. 16generally viewed from the opposite or reverse side;

[0047]FIG. 19 is a perspective view of the apron assembly of FIG. 16further showing a fender and headlights of the motor vehicle attached tothe apron assembly;

[0048]FIG. 20 is a perspective view of the modular front end of FIGS. 1and 2 showing only the structural components of the various assemblies;and

[0049]FIG. 21 is a second perspective view of the modular front endshown in FIG. 20.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] For purposes of the description hereinafter, the terms “upper”,“lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the invention, as it is oriented inthe drawing figures. However, it is to be understood that the inventionmay assume various alternatives and step sequences, except whereexpressly specified to the contrary. It is also to be understood thatthe specific elements and processes illustrated in the drawings, anddescribed in the following specification, are simply exemplaryembodiments of the invention. Hence, specific dimensions and otherphysical characteristics related to the embodiments disclosed herein arenot to be considered alimiting.

[0051] Referring to FIGS. 1 and 2, a motor vehicle 1 comprising amodular front end 10 in accordance with the present invention is shown.Only the front portion of the motor vehicle 1 is shown, but theremainder of the motor vehicle 1 is conventional. The modular front end10 forms the complete front portion of the motor vehicle 1. Onceassembled, the modular front end 10 may be attached to the body of themotor vehicle 1 substantially in one step, significantly increasing theefficiency of assembling the motor vehicle 1. The modular front end 10preferably arrives pre-assembled to the assembly line where it is joinedto the body of the motor vehicle 1. The modular front end 10 allows thelength of the assembly line to be reduced because the large number ofparts typically found in the front end of the motor vehicle 1 is nowconsolidated into several sub-modules or sub-assemblies, each of whichis described in detail hereinafter. The modular front end 10 alsoreduces the assembly equipment and the number of workers required tomanufacture the motor vehicle 1. Further, the individual assembliescomprising the modular front end 10 may be tested for performance priorto their installation in the modular front end 10, which improves theoverall quality of the motor vehicle 1.

[0052] The modular front end 10 is generally comprised of four (4)separate sub-modules or assemblies. The four distinct modules include abulkhead assembly 100, a drive train assembly 200, a crash energyabsorption assembly 300, and an apron assembly 400. The bulkheadassembly 100 generally provides the structural support for mounting andsupporting the other assemblies 200, 300, 400. The drive train assembly200 is directly attached to the bulkhead assembly 100. The crash energyabsorption assembly 300 is positioned generally around the lower portionof the drive train assembly 200 and is also directly attached to thebulkhead assembly 100. The apron assembly 400 is generally positioned ontop of the drive train assembly 200 and the crash energy absorptionassembly 300, and generally surrounds the drive train assembly 200. Eachof the assemblies 100-400 will be discussed in detail hereinafter, aswell as a preferred method of assembling the modular front end 10 of themotor vehicle 1.

[0053] The various assemblies 100-400 are independent of one another or“functionally de-coupled” from one another and are generallyinterrelated by their connection to the bulkhead assembly 100, whichprovides the structural support for the other assemblies 200-400. Thebulkhead assembly 100 may be provided separately from or pre-attached tothe body of the motor vehicle 1. Thus, the modular front end 10 may bepre-assembled and attached to the body of the motor vehicle 1, or thebulkhead assembly 100 may be pre-attached to the body of the motorvehicle 1 and the other assemblies 200-400 then attached to the bulkheadassembly 100.

[0054] Referring to FIGS. 1-7, the bulkhead assembly 100 is generallycomprised of a cast, preferably unitary, bulkhead 102 and a plurality ofcomponents or parts, such as structural members of the motor vehicle,attached to the bulkhead 102. The bulkhead 102 serves as the basestructural component that the supports the drive train assembly 200, thecrash energy absorption assembly 300, and the apron assembly 400.

[0055] The unitary bulkhead 102 is preferably an ultra-large casting ofaluminum or aluminum alloy or a similar material such as magnesiumalloy, or formed of fiber reinforced polymer composite materials. Thebulkhead 102 is a unitary bulkhead that replaces the typical 10 to 15stamped steel parts typically used in existing bulkhead designs. The useof aluminum and aluminum alloys reduces the weight of bulkhead 102 incomparison to traditional bulkhead designs. The bulkhead 102 may also beformed of multiple cast components, each preferably cast from aluminumalloy, and joined together by means customary in the art.

[0056] The bulkhead 102 is preferably cast with one or more hollowcavities 104 formed therein for increasing the strength and rigidity ofthe bulkhead 102. The hollow cavity 104 may be filled with acast-in-place core or polymeric foam 106. The cast-in-place core 106 ispreferably aluminum foam. When polymeric foam is used, the polymericfoam 106 is filled into the hollow cavity 104 after casting. Thecast-in-place aluminum foam core or polymeric foam 106 increases thestrength and stiffness of the system but also reduces the chance ofinternal corrosion in the bulkhead 102. The bulkhead 102 is generallyrectangular shaped and has opposite lateral ends 108, 110, and top andbottom ends 112, 114. The top end 112 of the bulkhead 102 may define alongitudinally extending opening 116, which may be used to route heatingand ventilating ducting as well as providing a drainage conduit forwater flowing off the windshield of the motor vehicle 1. The rectangularshaped bulkhead 102 has a first side 118 and a second side 120. Thefirst side 118 faces an engine compartment 122 defined by the modularfront end 10, and the second side 120 faces a passenger compartment 124of the motor vehicle 1.

[0057] The bulkhead 102 is preferably cast to have a plurality ofintegrally formed attachment mounts 126. The attachment mounts 126provide locations for attaching the drive train assembly 200, the crashenergy absorption assembly 300, and the apron assembly 400 to thebulkhead 102. Additionally, the attachment mounts 126 provide locationsfor attaching additional components of the bulkhead assembly 100 to thebulkhead 102. These additional components, discussed hereinafter, mayalso be attached directly to the top and bottom ends 112, 114 and firstand/or second sides 118, 120 of the bulkhead 102. The integralattachment mounts 126 generally provide specific locations for mountingthe various assemblies 200, 300, 400.

[0058] The bulkhead assembly 100 further includes additional parts orcomponents, such as structural members 128 or electrical components 130,of the motor vehicle 1. The structural members 128 may include, but arenot limited to, a pair of door hinge pillars 132, 134, a pair of rockerpanels 136, 138, a pair of windshield support pillars 140, 142, and awindshield cross member 144, each mounted to the bulkhead 102. Theelectrical components 130 may include, but are not limited to, anelectrical junction box 146 and a windshield wiper motor 148.

[0059] The pair of door hinge pillars 132, 134 is mounted to theopposite ends 108, 110 of the bulkhead 102. The door hinge pillars 132,134 are mounted to four (4) attachment 126 dp located on each of theopposite ends 108, 110 of the bulkhead 10. The door hinge pillars 132,134 provide mounting locations for mounting the doors of the motorvehicle 1.

[0060] The pair of rocker panels 136, 138 is mounted the bulkhead 102generally opposite from the door hinge pillars 132, 134. The rockerpanels 136, 138 are located and attached to the bottom end 114 of thebulkhead 102. The rocker panels 102 are, in turn, connected to the bodyof the motor vehicle 1 in a conventional manner.

[0061] The pair of windshield support pillars 140, 142 is mounted at thetop end 112 of the bulkhead 102. Preferably, the windshield supportpillars 140, 142 are mounted to two integral attachment mounts 126 wplocated at the top end 112 of the bulkhead 102. The windshield supportpillars 140, 142 are used to support a windshield 150 of the motorvehicle 1, as shown in FIG. 3. The windshield cross member 144 is alsomounted at the top end 112 of the bulkhead 102 between the windshieldsupport pillars 140, 142 to further support the windshield 150.

[0062] A pair of hood hinges 152 may be mounted to two (2) attachmentmounts 126 hh located on the first side 118 of the bulkhead 102. Thehood hinges 152 support a hood (not shown) of the motor vehicle 1 in aconventional manner, and may each include hood-lift assist mechanisms(i.e., air cylinders or springs), which are conventional in the art.

[0063] As stated previously, various electrical components 130 of themotor vehicle 1 may be attached to the bulkhead 102. In FIG. 3, twoexemplary electrical components 130 of the motor vehicle 1 are shownattached to the first side 118 of the bulkhead 102. The electricalcomponents 130 shown include the electrical junction box 146 and thewindshield wiper motor 148 of the motor vehicle 1. Additional attachmentmounts 126 formed on the first side 118 of the bulkhead 126 are used asattachment points for the drive train assembly 200, crash energyabsorption assembly 300, and apron assembly 400, as discussedhereinafter.

[0064] Referring to FIGS. 1-3 and 8-13, the drive train assembly 200 isattached to the first of the bulkhead 102 at four (4) specificattachment mounts 126 a, 126 b, 126 c, 126 d formed on the first side118, which are adapted to support the weight of the drive train assembly200. The drive train assembly 200 is generally comprised of a drivetrain support 202 and a power train assembly 204 attached to the drivetrain support 202. The drive train support 202 is comprised of a pair ofelongated support members 206, 208, which are preferably mechanicallyattached to the bulkhead 102 at the four (4) specific attachment mounts126 a-d on the first side 118 of the bulkhead 102. Each of the supportmembers 206, 208 has two (2) points of connection 209 to the bulkhead102. Preferably, the points of connection 209 between the supportmembers 206, 208 and the attachment mounts 126 a-d on the bulkhead 102each include a rubber isolation bushing or mount 211 for reducingvibration between the bulkhead 102 and the drive train assembly 200.These attachments are designed to be in orthogonal directions. Thesupport members 206, 208 are preferably cast aluminum or aluminum alloysupport members. However, the support members 206, 208 may be cast fromother similar metals such as magnesium and alloys thereof or ferrouscontaining metals and even non-metallic materials such as fiberreinforced polymer composite materials.

[0065] A cross member 210 interconnects the support members 206, 208.The cross member 210 is preferably mechanically connected to the supportmembers 206, 208. As used in this disclosure, the terms “mechanically”,“mechanically connected”, or “mechanical means” and similar phrases areintended to mean the use of mechanical fasteners such as nuts, bolts,rivets, and the like, and their substantial equivalents, and may includethe use of vibration isolation joints such as rubber bushings or similarresilient structures as necessary to reduce vibration and noise. Thecross member 210 is preferably an extruded aluminum alloy cross member,but may be a cast article and may be made of any of the materials listedpreviously in connection with the support members 206, 208. The supportmembers each have a top or upper end 212 and a bottom or lower end 214.The cross member 210 preferably connects the top or upper ends 212 ofthe support members 206, 208.

[0066] The power train assembly 204 is supported entirely by the supportmembers 206, 208 and bulkhead 102 in the modular front end 10. There isat least one and, preferably, multiple points of connection between thepower train assembly 204 and drive train support 202, as discussedhereinafter. As indicated previously, there are preferably four (4)points of connection between the drive train support 202 and thebulkhead 102 at attachment mounts 126 a-d. The support members 206, 208are attached to the bulkhead 102 and generally extend vertically alongthe bulkhead 102. Thus, the power train assembly 204 is cantileveredfrom the support members 206, 208 and the bulkhead 102 in the modularfront end 10. By “cantilevered” it is meant that the center of gravityof the power train assembly 204 is positioned outward from the bulkhead102 and drive train support 202. The attachment mounts 126 a-d at thetop and bottom ends 112 , 114 of the bulkhead 102 provide the verticalsupport for the power train assembly 204. The attachment mounts 126 a,126 b located at the bottom end 114 of the bulkhead 102 are horizontallyoriented so that the power train assembly 204 is supported in twoplanes, horizontal and vertical.

[0067] In summary, the power train assembly 204 is substantiallysupported in a “cantilevered” fashion by a substantially verticallyoriented power train support 202, which is connected to the bulkhead 102mechanically. This is in contrast to typical engine support arrangementscurrently used in the automotive industry in which a horizontallyextending engine cradle supports the engine of the motor vehicle. Theengine cradle in known engine support arrangements is rigidly connectedto the frame of the motor vehicle and supports the engine fromunderneath.

[0068] The power train assembly 204 generally includes an engine 216 anda transmission 218 of the motor vehicle 1. The engine 216 has numerouscomponents associated therewith, such as an engine manifold 220 and anengine exhaust 222. In this disclosure, the term “engine” 204 is meantto include the power generating unit of the motor vehicle 1 as well asany accessories directly connected thereto necessary for generatingpower for the motor vehicle 1. The engine 216 and transmission 218 aremechanically attached to the support members 206, 208 at multipleconnection or mounting points 219 as best shown FIGS. 11 and 12. Themounting points 219 may be vibration-isolated through the use of aplurality of rubber isolation bushings or mounts 221, again as bestshown in FIGS. 11 and 12.

[0069] Additional components of the modular front end 10 may besupported on the drive train support 202, either directly or indirectly.For example, the drive train assembly 200 may further comprise asteering gear 224 of the motor vehicle 1. The steering gear 224 of themotor vehicle 1 is housed within a housing 225. The steering gear 224 isattached to the bottom ends 214 of the support members 206, 208, withthe housing 225 interconnecting the support members 206, 208 at thelower end 214 of each of the support members 206, 208. The supportmembers 206, 208, cross member 210, and steering gear 224 and housing225 form a solid four (4) sided frame for supporting the power trainassembly 204. The steering gear 224 is conventional in the art and isconfigured to be connected to the steering column (not shown) of themotor vehicle 1

[0070] The motor vehicle 1 comprises two front wheels 226, 228. A brakeand suspension assembly 230 is associated with each of the front wheels226, 228 to interconnect the front wheels 226, 228 to the drive trainassembly 200 and, more particularly, the drive train support 202. Thebrake and suspension assembly 230 generally includes the componentsnecessary to apply braking to the front wheels 226, 228, andinterconnect the front wheels 226, 228 to the drive train assembly 200.The front wheels 226, 228 are respectively connected to two power trainshafts 232, 234, which extend outward from the transmission 218 andprovide power to the front wheels 226, 228.

[0071] The brake and suspension assemblies 230 each include a knuckle236, a braking assembly 238 connected to the knuckle 236, and a lowercontrol arm 240 connected to the knuckle 236. A sway bar 242 mayinterconnect the two (2) brake and suspension assemblies 230. Theknuckle 236 for each of the assemblies 230 is conventional and may beconnected by a shock absorber and spring assembly 244 to the top end 212of the support members 206, 208 in each assembly 230. The brakingassembly 238 (i.e., rotor, caliper etc.) is also conventional and issupported by the knuckle 236 in each of the assemblies 230. The knuckle236 in each assembly 230 is connected to the lower end 214 of therespective support members 206, 208 by respective lower control arms240. The lower control arms 240 are connected to the respective supportmembers 206, 208 mechanically, such as with bushings 246. The bushings246 may be rubber isolation bushings or mounts as are known in the art.The lower control arm 240 shown on the passenger's or left side of thedrive train assembly 200 (top portion of FIG. 13) is the subject matterof U.S. patent application Serial No. (not yet assigned) filed the sameday as this application, Oct. 16, 2002, and entitled “Control Arm ForMotor Vehicle Suspension System”, and naming Dinesh C. Seksaria and JohnW. Cobes as inventors. The disclosure of the foregoing United StatesPatent Application is incorporated fully herein by reference.

[0072] The drive train assembly 200 contains each of the componentsrequired to make the motor vehicle 1 move, stop, and steer. The drivetrain support 202 is specifically adapted to support the engine 216 andtransmission 218 in the vertical direction, such that the engine 216 andtransmission 218 are cantilevered from the bulkhead 102, as definedpreviously. The bulkhead 102 generally separates the engine compartment122 from the passenger compartment 124 in the motor vehicle 1. Theengine 216 and transmission 218 are now located directly in front of thebulkhead 102 providing an extra layer of protection for occupants of thepassenger compartment 124 in the event of a front end collision.Additionally, the engine 216, transmission 218, steering gear 224, andbrake and suspension assemblies 230 for the two front wheels 226, 228are all now compacted tightly within a single sub-assembly, which may bepre-tested as a unit before assembly to the motor vehicle 1. The compactnature of the drive train assembly 200 also provides a more direct andshorter path for exhaust gases from the engine 216, which improvesperformance and fuel efficiency of the engine 216 while reducingemissions. The compact form of the drive train assembly 200 frees upadditional space for expanding the passenger compartment 124 of themotor vehicle 1. Furthermore, the weight of the engine 216 andtransmission 218 is centered substantially directly over the wheel axisof the front wheels 226, 228, which will improve the traction andhandling of the motor vehicle 1.

[0073] Referring to FIGS. 1-3 and 14 and 15, the crash energy absorptionassembly 300 is attached to the first side 118 of the bulkhead 102 attwo attachment mounts 126 e, 126 f generally located laterally outsideof the attachment mounts 126 a-d for the drive train assembly 200. Thecrash energy absorption assembly 300 is preferably fixedly mounted tothe two attachment mounts 126 e, 126 f. The crash energy absorptionassembly 300 is used to absorb impact energy during a collisioninvolving the modular front end 10 of the motor vehicle 1 and to managethe energy to avoid injury to occupants of the passenger compartment124. The crash energy absorption assembly 300 is pre-assembled andattached to the bulkhead 102 in a similar manner to the drive trainassembly 200 discussed hereinabove.

[0074] The crash energy absorption assembly 300 is generally comprisedof an elongated bumper beam 302, a pair of brackets 304, 306, and a pairof elongated tubes 308, 310. The brackets 304, 306 are attached to thebumper beam 302, preferably by mechanical means. The brackets 304, 306are preferably taper and flare brackets. In FIGS. 14 and 15 only theright side or driver's side bracket 304 is illustrated as a taper andflare bracket. The left or passenger's side bracket 306 (top of FIGS. 14and 15) is illustrated as a conventional bracket. The term “brackets304, 306” is intended to represent both taper and flare and conventionalbrackets in this disclosure. A suitable taper and flare bracketarrangement for the brackets 304, 306 is disclosed in U.S. patentapplication Ser. No. 09/932,673 to Summe et al., which is assigned tothe common Assignee of this application, and is incorporated herein byreference in its entirety. The brackets 304, 306, when provided as taperand flare brackets, perform the function of tapering and flaring thetubes 308, 310 from the bumper beam 302. When the brackets 304, 306 areconventional brackets, the elongated tubes 308, 310 are preferably crushtubes, which accommodate impact energy involving the modular front end10 and the crash energy absorption assembly 300.

[0075] The tubes 308, 310 each have a first end 312 and a second end314. The first ends 312 of the tubes 308, 310 are supported by thebrackets 304, 306. The brackets 304,306 each define a socket 316 forreceiving and supporting the tubes 308, 310. The first ends 312 of thetubes 308, 310 are received and secured in the sockets 316 defined bythe brackets 304, 306, preferably by mechanical means, which may includean interference fit. The second ends 314 of the tubes 308, 310 areconfigured for connection to the two outer attachment mounts 126 e, 126f formed on the first side 118 of the bulkhead 102. The tubes 308, 310may be made of aluminum or aluminum alloy such as 7003 T6, 6082 T6aluminum alloys, other aluminum alloys such as 6061 T6 aluminum alloy,high strength steels, or non-metallic materials such as fiber reinforcedpolymer composite materials. Any of the 6XXX and 7XXX aluminum alloys asdesignated by the Aluminum Association may be used for the tubes 308,310.

[0076] The tubes 308, 310 may be at least partially or fully filled withpolymeric foam 318. Preferably, the polymeric foam 318 is located atleast within the second ends 314 of the tubes 308, 310. The tubes 308,310 have hollow cross sectional profiles for receiving the polymericfoam 318. The tubes 308, 310 may have different cross sectionalprofiles, but it is generally preferred that the tubes 308, 310 have thesame cross sectional profiles. As shown in FIGS. 14 and 15, the crosssectional profiles for the tubes 308, 310 may be oval or a polygonalshape such as a double hexagon, “figure-8” profile. Other possible crosssectional profiles for the tubes 308, 310 include circular, square,rectangular, and combinations of these profiles and the oval andhexagonal profiles illustrated. Oval or circular cross sectionalprofiles are preferred for use with taper and flare brackets, while anyof the cross sectional profiles indicated hereinabove may be used whenthe tubes 308, 310 are provided as crush tubes, which are used withtraditional, for example stamped steel, brackets.

[0077] As stated previously, the brackets 304, 306 may be both taper andflare brackets, or both conventional brackets. In FIGS. 14 and 15, theleft (passenger's) side bracket 306 is illustrated as a conventionalbracket while the right or driver's side bracket 302 is illustrated as ataper and flare bracket. When the brackets 304, 306 are conventional(i.e., can be made of any specified material but the design isconventional), the tubes 308, 310 are provided as crush tubes thatabsorb crash energy by crushing or collapsing during a collisioninvolving the modular front end 10.

[0078] The bumper beam 302 has a generally curved shape. Since thebumper beam 302 has a generally curved shape, front impact forces on thebumper beam 302 will generate a significant cross spreading force. Tocounter this, the brackets 304, 306 are connected by a crosstie 320,which manages the transverse spreading force. The crosstie 320interconnects the brackets 304, 306 for stability. The bumper beam 302,brackets 304, 306, and tubes 308, 310 are preferably each made ofaluminum or aluminum alloy. The bumper beam 302 is preferably made of6013 T6 or 6061 T6 aluminum sheet that is roll formed into an open crosssectional shape. The bumper beam 302 may be made of an aluminum alloyselected from the 6XXX or 7XXX series aluminum alloys. Generally, thebumper beam 302 defines an open cross sectional shape that is at leastpartially, preferably completely, filled with polymeric foam 322. Thebumper beam 302 may also be made of other aluminum alloys such as 7003T6 or 6082 T6 aluminum alloys, or other alloys selected from the 6XXX or7XXX series aluminum alloys, or be made from high strength steel sheet.The bumper beam 302 preferably defines a substantially Σ-shaped opencross section. The substantially Σ-shaped cross section comprises a rearwall 324 connected to substantially parallel top and bottom walls 326,328. A suitable bumper beam 302 having the Σ-shaped open cross sectiondescribed hereinabove is found in U.S. Pat. No. 6,308,999 to Tan et al.assigned to Alcoa Inc., Pittsburgh, Pa., the common assignee of thisapplication, and is incorporated herein in its entirety.

[0079] The brackets 304, 306 are preferably aluminum alloy extrusionsand are preferably taper and flare brackets as indicated previously.Suitable aluminum alloys for the taper and flare brackets include 7003T6 and 6082 T6 aluminum alloys. Again, however, the taper and flarebrackets 304, 306 may be made of an aluminum alloy selected from the6XXX or 7XXX series aluminum alloys. The brackets 304, 306 may also bemade from other materials such as high strength steel and non-metalliccomposite materials such as polymer fibers such as carbon, glass, orarimid. The brackets 304, 306 are preferably mechanically attached tothe bumper beam 302 opposite the rear wall 324 in the Σ-shaped crosssection of the bumper beam 302.

[0080] The crash energy absorption assembly 300 is provided as apre-assembled unit for attachment to the bulkhead 302 in a similarmanner to the drive train assembly 200 discussed previously. The use ofaluminum or aluminum alloys in the components of the crash energyabsorption assembly 300 reduces the weight of the assembly 300 withoutsacrificing the energy absorbing requirements of the assembly 300.Further, the positioning of the crash energy absorption assembly 300generally around the drive train assembly 200 enhances the overallcompactness of the modular front end 10 of the present invention.

[0081] Referring to FIGS. 1-3 and 16-19, the apron assembly 400 isgenerally positioned on top of the drive train assembly 200 and thecrash energy absorption assembly 300. The apron assembly 400 ispre-assembled and attached to the bulkhead 102 in a similar manner tothe drive train assembly 200 and crash energy absorption assembly 300discussed previously. The apron assembly 400 generally extends aroundthe circumference of the engine compartment 122 defined by the modularfront end 10. The apron assembly 400 generally collects themiscellaneous engine accessories of the motor vehicle 1 and providesconvenient locations for mounting these accessories.

[0082] The apron assembly 400 is generally comprised of a unitary apronmember 402 having a depending front portion 404 and an apron rail 406attached to a top end of the apron member 402. The apron member 402 issubstantially C-shaped. The apron member 402 preferably defines aplurality of integrally formed accessory attachment mounts 408. Theapron 406 rail is also substantially C-shaped and is attached to the topend of the apron member 402. The apron rail 406 has two ends 410, 412configured for attachment to the bulkhead 102. In particular, the ends410, 412 are configured for connection to two (2) attachment mounts 126g, 126 h located adjacent the top end 112 of the bulkhead 102. Theconnections between the ends 410, 412 and the attachment mounts 126 g,126 h are preferably made by mechanical fasteners.

[0083] The apron member 402 is preferably a unitary member made ofmolded plastic having the accessory attachment mounts 408 integrallyformed therewith. The apron rail 406 is preferably a one-piece,aluminum, and preferably hydro-formed rail having differing crosssections along its length and is attached to the apron member 402mechanically. The differing cross sections provide additional locationsfor mounting front end accessories used in the modular front end 10. Theaccessory attachment mounts 408 may include integrally formed mountingpoints or openings defined in the apron member 402 for supportingvarious front end accessories

[0084] As stated, the apron assembly 400 generally collects themiscellaneous front end engine accessories of the motor vehicle 1, whichotherwise must be individually assembled to the front end of the motorvehicle 1. Examples of such accessories include, but are not limited to,the radiator, coolant overflow bottle, transmission oil cooler, airconditioner condenser, fans, headlights, horn, battery, electrical fusebox, integral wire harnesses, windshield wiper washer fluid bottle, andair pump, etc. Several of the larger and more complex front end engineaccessories will be discussed hereinafter. The smaller front endaccessories, such as the coolant overflow bottle and windshield wiperwasher fluid bottle (not shown), easily attach to the apron member 402at the accessory attachment mounts 408 by mechanical fasteners, as willbe appreciated by those skilled in the art.

[0085] The front portion 404 of the apron member 402 defines a pluralityof openings, hereinafter identified as first opening 414, second opening416, and third opening 418. The first opening 414 is formed centrally inthe front portion 404 and supports a radiator and cooling fan assembly420. The radiator and cooling fan assembly 420 is supported in the firstopening 414 by conventional means, such as mechanical fasteners. Thesecond opening 416 is defined adjacent the first opening 414 andsupports an air conditioning condenser 422 of the motor vehicle 1. Thethird opening 422 is defined on the other side of the first opening 414and supports a transmission oil cooler 424. The air conditioningcondenser 422, and transmission oil cooler 424 may be fixed in therespective second and third openings 416, 418 by conventional means(i.e., mechanical fasteners).

[0086] The apron member 402 further comprises an integrally formedbattery hold-down 426 for supporting a battery 426 of the motor vehicle1. The battery 428 may be supported in the battery hold-down 426 bymeans conventional in the art, such as straps and mechanical fasteners.

[0087] The apron assembly 400 provides a lightweight structure forcollecting and supporting the miscellaneous front end accessoriesrequired for the motor vehicle 1. The apron assembly 400 ispre-assembled in a similar manner to the drive train assembly 200 andthe crash energy absorption assembly 300. Each of the accessoriesattached to the apron member 402 may be pretested prior to the apronassembly 400 being attached to the bulkhead 102. A similar procedure maybe followed for the power train assembly 204, steering and brakingassembly 224, and axle assembly 240 in the drive train assembly 200.

[0088] Furthermore, the apron assembly 400, particularly the apron rail406, provides a convenient mounting structure for fenders 430 and otherfront end components of the motor vehicle 1, as indicated previously.Additionally, headlights 432 of the motor vehicle 1 may be attached tothe front portion 404 of the apron member 402, which provides aconvenient location for supporting the headlights 432 of the motorvehicle 1. The fenders 430 and headlights 432 may be attached to theapron assembly 400 by conventional means (i.e., mechanical fasteners andthe like).

[0089] With the respective “modular” sub-assemblies 100-400 nowdescribed, a method of assembling the modular front end 10 forattachment to the motor vehicle 1 will now be discussed with referenceto FIGS. 1-21. The method of assembling the modular front end 10generally begins with providing the bulkhead assembly 100 having thestructural members 128 and electrical components 130 pre-attachedthereto. The bulkhead 102 of the bulkhead assembly 100 provides the mainstructural member for supporting each of the pre-assembledsub-assemblies 200-400 to follow. The bulkhead 102 may be providedseparate from the body of the motor vehicle 1, or pre-attached to thebody of the motor vehicle 1. The various assemblies 200-400 may then bemounted to the pre-attached bulkhead 102.

[0090] Next, the drive train assembly 200 is attached to the bulkhead102 at the four (4) drive train assembly attachment mounts 126 a-dlocated on the first side 118 of the bulkhead 102. FIGS. 20 and 21 showthe “structural elements” of the respective assemblies 100-400, with all“accessories” omitted for clarity in showing the mounting connectionsfor the drive train assembly 200, crash energy absorption assembly 300,and apron assembly 400. As described previously, the drive train support202 is affixed directly to the bulkhead 102. The power train assembly204, which generally comprises the engine 216 and transmission 218 ofthe motor vehicle 1, is cantilevered from the drive train support 202and bulkhead 102. The drive train assembly 200, as discussed previouslyis provided pre-assembled, with the power train assembly 204pre-attached to the drive train support 202 and the engine 216 andtransmission 218 pre-tested. The steering gear 224, which is connectedto the steering column of the motor vehicle 1, interconnects the lowerends 214 of the support members 206, 208 to form a solid box framestructure, as described previously. The brake and suspensions assemblies230 may be connected to the drive train support 202 in the mannerdescribed previously and pre-tested for function.

[0091] Once the drive train support 202 and pre-tested power trainassembly 204 are attached to the bulkhead 102, the crash energyabsorption assembly 300 may be attached to the bulkhead 102 at theattachment mounts 126 e, 126 f, which are generally located outside ofthe drive train support 202 attachment mounts 126 a-d used to supportthe drive train assembly 200. The crash energy absorption assembly 300is provided pre-assembled such that it is only necessary to attach thesecond ends 314 of the tubes 308, 310 to their corresponding attachmentmounts 126 e, 126 f on the first side 118 of the bulkhead 102.

[0092] With the drive train assembly 200 and the crash energy absorptionassembly 300 attached to the bulkhead 102, the apron assembly 400 may beattached to the bulkhead 102. The apron assembly 400 is attached to thebulkhead 102 by affixing the ends 410, 412 of the apron rail 406 at theapron assembly attachment mounts 126 g, 126 h generally located adjacentthe top end 112 of the bulkhead 102. The apron member 402 is partiallysupported in the vertical direction by the tubes 308, 310. Inparticular, a bottom end of the front portion 404 of the apron member402 rests on the tubes 308, 310 to provide vertical support for theapron assembly 400. The front portion 404 of the apron member 402 may beattached to the crosstie 320 connecting the brackets 304, 306 in thecrash energy absorption assembly 300. An adhesive may be used betweenthe bottom end of the front portion 404 of the apron member 402 and thesurfaces of the tubes 308, 310 to further secure the apron assembly 400to the crash energy absorption assembly 400. All attachments between thedrive train assembly 200, crash energy absorption assembly 300, andapron assembly 400 and the bulkhead 102 are preferably made withmechanical fasteners. Rubber bushings or mounts as discussed previouslymay be used in the connections between the drive train assembly 200 andthe bulkhead 102 to isolate these assemblies and minimize vibration asindicated previously.

[0093] In an alternative method of assembly, the apron assembly 400 maybe attached first to the crash energy absorption assembly 300. This“combined” assembly (crash energy absorption assembly 300 and apronassembly 400) may then be attached as a unit to the bulkhead 102. Thecombined crash energy absorption assembly 300 and apron assembly 400 isthen attached to the bulkhead 102 in the manner described previously.Once again, the bulkhead 102 may be detached from or pre-attached to thebody of the motor vehicle 1.

[0094] The modular front end of the present invention results in higherquality motor vehicles and reduced costs to the manufacturer. Motorvehicle assembly lines may be shortened because the “sub-modules” orsub-assemblies described hereinabove collect numerous individual partsthat previously had to be individually assembled to the motor vehicle.Accordingly, an increased number of car bodies may be put through theassembly line in a given period of time. The modular front end alsoreduces the mass of the motor vehicle, which improves performance andthe fuel efficiency of the motor vehicle. Additionally, the modularfront end preferably uses mechanical fasteners at all connection pointsrather than metallurgical joints, which reduces production time andcost. In general, the modular front end of the present inventionimproves the speed and quality at which motor vehicles are constructed.

The invention claimed is:
 1. An apron for a front end of a motorvehicle, comprising: a substantially C-shaped, unitary apron memberhaving a depending front portion, the apron member defining at least oneintegrally formed accessory attachment mount for mounting at least oneengine accessory of the motor vehicle thereto; and a substantiallyC-shaped apron rail attached to a top end of the apron member andconfigured for attachment to a bulkhead of the motor vehicle.
 2. Theapron of claim 1, wherein the apron member is formed of molded plasticmaterial and the apron rail is made of aluminum alloy.
 3. The apron ofclaim 1, wherein the at least one accessory attachment mount comprises aplurality of openings defined in the front portion.
 4. An apron assemblyfor a front end of a motor vehicle, comprising: a substantiallyC-shaped, unitary apron member having a depending front portion, theapron member defining at least one integrally formed accessoryattachment mount; a substantially C-shaped apron rail attached to a topend of the apron member and configured for attachment to a bulkhead ofthe motor vehicle; and at least one engine accessory of the motorvehicle attached to the apron member at the at least one accessoryattachment mount.
 5. The apron assembly of claim 4, wherein the apronmember is formed of molded plastic material and the apron rail is madeof aluminum alloy.
 6. The apron assembly of claim 4, wherein the apronrail is configured for mechanical attachment to the bulkhead.
 7. Theapron assembly of claim 4, wherein the at least one accessory attachmentmount comprises a plurality of openings defined in the front portion. 8.The apron assembly of claim 4, wherein the engine accessory is aradiator and cooling fan assembly and the accessory attachment mount isan opening defined in the front portion of the apron member, theradiator and cooling fan assembly supported in the opening.
 9. The apronassembly of claim 4, wherein the engine accessory is an air conditioningcondenser and the accessory attachment mount is an opening defined inthe front portion of the apron member, the air conditioning condensersupported in the opening.
 10. The apron assembly of claim 4, wherein theengine accessory is a transmission oil cooler and the accessoryattachment mount is an opening defined in the front portion of the apronmember, the transmission oil cooler supported in the opening.
 11. Theapron assembly of claim 4, wherein the engine accessory is a battery andthe accessory attachment mount is an integrally formed batteryhold-down, the battery supported in the battery hold-down.
 12. The apronassembly of claim 4, further comprising fenders attached to the apronrail.
 13. The apron assembly of claim 4, further comprising headlightsattached to the front portion of the apron member.
 14. A method ofassembling an apron assembly for a front end of a motor vehicle,comprising the steps of: providing a unitary apron member having adepending front portion, the apron member defining at least oneintegrally formed accessory attachment mount; attaching an apron rail toa top end of the apron member; and attaching at least one engineaccessory of the motor vehicle to the apron member at the at least oneaccessory attachment mount.
 15. The method of claim 14, wherein theengine accessory is a radiator and cooling fan assembly and theaccessory attachment mount is an opening defined in the front portion ofthe apron member, the method further comprising the step of supportingthe radiator and cooling fan assembly in the opening.
 16. The method ofclaim 14, wherein the engine accessory is an air conditioning condenserand the accessory attachment mount is an opening defined in the frontportion of the apron member, the method further comprising the step ofsupporting the air conditioning condenser in the opening.
 17. The methodof claim 14, wherein the engine accessory is a transmission oil coolerand the accessory attachment mount is an opening defined in the frontportion of the apron member, the method further comprising the step ofsupporting the transmission oil cooler in the opening.
 18. The method ofclaim 14, wherein the engine accessory is a battery and the accessoryattachment mount is an integrally formed battery hold-down, the methodfurther comprising the step of supporting the battery in the batteryhold-down.
 19. The method of claim 14, further comprising the step ofattaching fenders to the apron rail.
 20. The method of claim 14, furthercomprising the step of attaching headlights to the front portion of theapron member.